Fluidic nozzles have been used in a variety of fluid dispersal applications such as oral irrigators, massaging shower heads, windshield washer nozzles, defrosters, etc. In order to function properly, fluidic oscillators need to have proper sealing so as to not cause leaking across flow channels. The typical construction for the fluidic oscillator has been to fabricate the fluidic circuit in one surface and sealed with another surface. FIG. 1 depicts a crossover-type fluidic element 10 formed in a body member 11. Recesses 13 are typically formed in surface 12 by injection-molding, and a cover plate 16 is placed against a surface to seal the fluidic element. In U.S. Pat. No. 4,185,777, the fluidic circuit element 20 is injection-molded in a chip member 21 which is then sealed by abutting the surface against another member, and in order to prevent leakage, the molded element is force-fitted into a housing 22. (See FIG. 2.) In U.S. Pat. No. 5,213,269, a low-cost, low-pressure feedback free-passage oscillator is disclosed which has no control ports and is molded in one piece 30 with a closure plate 31 hingedly 32 connected to the main body of the device and folded and latched. (See FIG. 3.)
The object of the present invention is to provide a method of molding a fluidic oscillator device having a power nozzle for projecting a jet of liquid into an interaction region having an upstream end, opposing side walls and a pair of control ports at the upstream end, one control port juxtaposed to the respective sides of the interaction region. A mold cavity is provided in which the power nozzle, interaction region and control ports can be molded as a core without any seam lines, and the mold cavity is filled with a solidifieable plastic which is then removed from the mold for use. In this way, all volumetric spaces forming the fluidic element are formed as closed bodies without any seam lines, thereby negating the need for assembling two halves of a fluidic circuit as done in the prior art. The invention also reduces manufacturing process variability due to the no-seal of the fluidic assembly. This also results in a reduction of scrap.
In case of a fluidic oscillator circuit of the type having a crossover interaction region, the interaction region is separated or split transverse to the direction of fluid flow in the interaction region, and the channels and volumetric spaces are designed so that there is no dielock, and the two halves can be separated.
A further object of the invention is to provide a downstream attachment with an exit throat, the attachment being capable of being designed to provide a range of desired output with respect to the extent of oscillation and the inclination of the output jet relative to the body of the fluidic oscillator.
A further object of the invention is to provide a method of constructing a fluidic oscillator device having at least a power nozzle for projecting a jet of liquid into an interaction region with an upstream end, opposing side walls, opposing top and bottom walls, and a pair of control ports at the upstream end, one control port juxtaposed to the respective sides of the interaction region. The side walls diverge from the power nozzle and the control ports having an aperture, the further improvement wherein there is provided top and bottom plates with channels which, with an inertance passthrough or link, form an inertance loop controlling the frequency of oscillation. The body of fluidic is capable of assembly with the top and bottom inertance plates with different lengths of inertance loops, thereby providing oscillations with different operating frequencies.
There is provided a method of constructing fluidic oscillator devices which have a main molded body portion to which may be attached an output exit throat which is capable of being designed to provide a range of desired outputs with respect to the extent of oscillations and the inclination of the output relative to the body of the fluidic oscillator and which is also capable of having inertance plates with channels therein which form inertance loops for controlling the frequency of oscillation.
A further object of the invention is to provide a method of manufacturing a fluidic element in which tooling the fluidic by changing the injection mold tooling is easier and less costly with this method.
In the case of the crossover type fluidic oscillator being formed, the assembly work involves joining the front half of the fluidic formed as a core to the rear half of the fluidic oscillator joining its two external inertance plates to the body of the fluidic. Both these actions can be considered external to the main part of the fluidic (power nozzle-control port-interaction region areas). The method also allows for the same fluidic to be assembled with different inertance plates, resulting in different operating frequencies. Similarly, the fluidic can be paired with different exit throats resulting in many different spray formats.